Wood preservation method and package



Feb. 24, 1959 R. G. RING woon PRESERVATION METHOD AND PACKAGE Filed Nov. 5, 1956 United States Patent() 2,875,020 p woon PRESERVATION METHOD AND PACKAGE `Applicaties November 5, 1956, serial Nd. 620,319 6 claims. (ci. 21-7) This invention relates to the preservation of wood and,more particularly, to a method of preserving wood and a package and assembly for wood preservation.

Wooden objectsset in or in contact with the soil yare subject `to attack by various organisms which cause wood decay and deterioration. Such organisms are present to a` substantial extent in the top layers of the soil and tend toattack such wooden `objects particularly along the ground line or immediate vicinity thereof. t ,l l

It is well4 known that pentachlorophenol is one of the most effective wood preservatives and the one used almost universally.` It is alsoknown that timbers may be protected against attack from such organisms by an initial pre-treatment which involves submerging the timbers in a vat containing pentachlorophenol in a suitable solution so that effective penetration of the wood is attained over the period of time that the wood is immersed in the solution. In the case of timbers, posts or other wooden objects `already mounted in the ground, however, this procedure is not possible. Also, the application of conventional preservative compositions to such wooden objects is not particularly effective, because the compositionsare taken `up by the soil wooden object to such an extent that only a negligible amount of preserving effect isobtained.

British` Patent No. 699,207 (published November 4, 1953), makes reference to a grease-like substance which line and which adheres to thefwooden object suiciently to 'permit penetration of the surface of the Wood with pentachlorphenol in a suitable carrier medium, so that effective wood preservation is obtained. The diiculty with this grease-like composition is primarily a practical consideration in that the material is very diicult to handle. It is actually a little `too viscous to be applied with a brush by a` painting technique. lt can be applied by the use of a trowel, but this is quite time-consuming and also quite awkward because the material tends to stick to almost anything it contacts including the trowel, and the hands and clothes of the worker Iapplying the material. t t

` The instant invention affords a novel package for use in the application of a carrier of grease-like consistency for the pentachlorophenol. In the instant package the grease-like carrier is enclosed in a tube or sleeve of o il impermeable material such as a synthetic plastic. If a flat layer of the grease-like material, enclosed in a synthetic plastic sleeve, is employed as such, however, additional diiiiculties are encountered because the oil impervious sleeve must be opened in orderto effectcontact between the wooden object and the grease-like substance. If, for example, the portion of the sleeve on one side of the layer of grease-like substance is to be removed in an effort to obtain an exposed surface of the layer of active material, it will be found that the grease-like substance adheres so well to the portion of the sleeve that one attempts to remove that a hopeless` mass is` created.

2,875,020 Patented Feb. 24, 1959 the synthetic resin iilm and one side `of the layer of and/ or leached from the `can be applied to thewooden objects along the ground Vpenetration of the barrier.`

. adherence which may be elfected can be grease-like material. In this way it is possible to remove the portion of the synthetic resin sleeve when it is desired to open the package for use on a post. or other wooden ,-object. It must further be appreciated that the barrier itself adheres as strongly or more so, than the synthetic resin iilm when in direct Contact with the grease-like substance, so once the synthetic resin film portion facing theWbarrier has been removed, the operator is still faced with a difficult problem. Neither the-` barrier nor the portion of the synthetic resin sleeve directly contacting the other side of the grease-like layer can be stripped therefrom with ease or by `any practical operation; Y In the instant invention, however, this problem is solved Iby employing a barrier which permits limited penetra` tion thereof by the carrier for the pentachlorophenol.

In this way the carrier itself is wrappedv around the wooden object, in direct contact therewith, and the pentachlorophenol carrier penetrates the barrier and the surface portions of the wooden object. Such penetration is assisted by the natural ainity between the pentachloro` phenol carrier and wood. In addition, the synthetic resin film in contact with the out or back side of the grease-like layer protects the same against erosion by weather'and Vthe like so as to prolong the process of The barrier is a porous iibrous sheet which permits limited relatively slow penetration thereof by `the pentachlorophenol carrier so that the back side of the barrier to which the synthetic resin film is exposed during normal storage prior to use does not adhere appreciably to the barrier. Any such slight easily overcome so that the barrier and the synthetic resin film engaging the same can be readily separated, even though the synthetic resin film functions in the initial package to prevent completely any leakage of oil or other materials from the' entire package.

It is, therefore, an important object of the instant invention to provide an improved wood preservative package, an improved assembly for protecting a wooden object, and an improved method of preserving a wooden object.

It is another object of the instant invention to provide an improved wood preserving package comprising a porous fibrous sheet, a layer on one side only of said sheet of an inert carrier of grease-like consistency containing at least 2% of pentachlorophenol, and a synthetic resinous film completely enclosing the sheet and layer. Still another object of the instant invention is to provide an improved wood preservative assembly comprising a wooden object, a porous fibrous sheet wrapping the object with one side of the sheet in direct contact with the object, a layer on the opposite side of the sheet of an inert carrier of grease-like consistency containing at least 2% of pentachlorophenol, and a synthetic resinous film covering the layer and sheet.

Yet another object of the instant invention is to provide an improved method of preserving a wooden object which comprises (l) providing a wood preservative package comprising a porous fibrous sheet, a layer on one side only of said sheet of an inert carrier of` grease-like consistency containing at least 2% of pentachlorophenol, and a synthetic resinous film completely enclosing the sheet and layer; (2) removing the film from the side of the sheet opposite said layer to expose the sheet;`

with the exposed the object.

(3) and wrapping the wooden object side of the sheet in direct contact with and the drawings attached hereto and made a part hereof.

On the drawings; Figure 1 is a sectional elevational view of a package embodying the instan'trin'vention; and

Figure 2 is a sectional elevational view of an assembly embodying the instant invention showing the package of Figure 1 wrapped around a wooden post.

As shown on the drawings:

In Figure l, a package indicated generally by the reference numeral is shown. The package 10 comprises a porous fibrous sheet 11 extending the full width of a generally fiat package 10, a layer 12 coextensive with and on one side only of the sheet 11 composed of an inert carrier of grease-like consistency containing pentachlorophenol, and a synthetic resinous film indicated generally by the reference numeral 13 completely enclosing the sheet 11 and layer 12. As will be seen the' film 13 defining the sleeve has a bottom portion 13a that is. coextensive with and in direct contact with the bottom of the sheet 11. The sleeve or film 13 also has a top portion 13b which is coextensive with and in contact with the top of the grease-like layer 12. The sleeve 13 is completedV by side portions 13C and 13d integral with the sarily so (and glass, fibers or the like may be used). A

principal function f the sheet 11 is that it permits limited permeation by the pentachlorophenol carriers, so

that ultimately the pentachlorophenol will be permitted to penetrate the wood which the sheet 11 contacts in the final assembly. On the other hand, the sheet 11 is sufficiently integral to resist destruction through relatively minor adhesion forces when the film portion 13a at the bottom of the package is removed from the bottom of the sheet 11. Also, the sheet 11 is sufiiciently resistant to permeation by the grease-like material 12 to effectively reduce the tendency for the grease-like material 1,2 to cause maximum adhesion between the sheet 11 and the film layer 13a. The materials employed in and the consistency of the grease-like material 12 will have some effect on the selection of the best type of sheet materialgforV the sheet 11, but muslin has been found to be best for this type of service using the preferred grease-like substances.

The sleeve or film 13 is an integral flexible self-sustaining film of oil impervious and waterrimpervious material. The film 13 in the initial package 10 serves to permit storage of the package 10, without any harmful leaching effect by contact with water and without having oil leakage from the package 10. Preferably, the film 13 is made of a sleeve of synthetic resinous material, which includes films of polyethylene, polyvinyl compounds (such as acetate, chloride, alcohol or combinations thereof) polyvinylidene chloride-polyvinyl chloride copolymers, cellulose acetates and ethers, regenerated cellulose, etc., any of which may be specially treated or coated to improve water and oil impermeability.

Preferably polyethylene is employed, because this material is commercially available and the most economical film that satisfies all needs. 4 e

The thicknesses of the sheet 11 and the film 13 are primarily a matter of selection to s uit the particular needs. The polyethylene film can, of course, be quite thin since these films are very tough and are not easily ruptured during ordinary handling. The fibrous lsheet 11 is ordinarily substantially thicker so that it may lmore easily function asa barriert'olimit the rate and extent of permeation thereof by the grease-like material 12.` Also, the size of 4 the sheet 11 and the sleeve 13 may be varied, with the exception that the sheet 11 is substantially one-half the circumference of the sleeve 13 in width. In this way the sheet 11, grease layer 12, and top and bottom films 13a and 13b are all substantially coextensive in width and in length.

The layer 12 is composed of a material having a grease-like consistency and containing at least about 2% of pentachlorophenol. (As used herein, the terms parts and percen mean parts and percent by weight, unless otherwise designated.) The preferred grease-like composition for use in the practice of the instant invention is described in detail in the aforementioned British Patent No. 699,207. This composition is an aromatic petroleum oil gel. In general, it comprises a combination of an aromatic oil and a polyvalent metal salt of a C12-C18 `fatty acid combined in proportions to obtain a grease-like consistency and containing from about 2% to about 15% pentachlorophenol. The aromatic. oil is a solvent for the pentachlorophenol and the principal carrier therefor which permeates the sheet 11 and ultimately the surface o-f the wooden object to be preserved. The fatty acid `i salt functions as a thickener in the formation of the gel.

The polyvalent metal salts of fatty acids which may be used include aluminum, magnesium, calcium, barium, zinc, etc. salts of aluric, palmitic, myristic, stearic, oleic, etc. acids, but the preferred thickener is aluminum stearate.

The oil used is generally described as an aromatic petroleum oil or sometimes called an aromatic gas oil or a heavy recycle oil. A preferred oil is a heavy recycle oil having a boiling point of about 601)#760ov F. Other oils which may also be used include cracking stocks, slurry oils, heavy aromatic gas oils Vand medium aromatic gas oils, examples being Root heavy thermal sidecut No. 195, Root No. 102E oil, Tidewater No. 200 dieseloil, Tidewater CGB oil, Denver No. 3 oil, Root No. 101B oil, and Magnolia lube oil extract No. 465B. Another reason why polyethylene is preferred for the film 13 inthe practice of the instant invention is that it is particularly re.- sistant to permeation by such oils. In general, the greaselike composition is formed using 5 to15% of the fatty acid salt thickener, 2 to 15 pentachlorophenol andthe remainder the aromatic oil. Such compositions are characterized by an A. S. T. M. worked penetration of from 200 to 35() millimeters at 77 F. The aromatic oil itself should have a viscosity not greater than 200 Saybolt Uni-y versal seconds at F. t

As a specific example, a grease-like composition is prepared according to standard practice for the formaf tion of petroleum oil gels using 10 parts pentachlorophenol, l0 parts aluminum distearate, and 80 parts heavy recycle oil (boiling range 600-760 F.). This composi-` tion may be designated Formulation I. The sheet 1 ,1 of muslin is slipped into the polyethylene sleeve 13 (ap-l proximately 11/2 feet in width and 2 feet in length and sealed at one end). The grease-like composition, is pumped between the muslin 11 and side 13b while excluding air. The open end of the sleeve 13 is then sealed and the package pressed fiat (to about 1A. inch'thickness). Also, the muslin 11 and sleeve 13 lmay be. placed in a die conforming to the desired final shape of the package 10 and the composition may then be pumped in. The package 10 was stored for a sixty day period. At the end of this time a slight odor of oil is noticeable and the polyethylene lm 13 has a slightly oily touch, but no appreciable penetration of oil has taken place, and n0 staining of a paper on which the package was stored is noticeable, so as to indicate that a minimum amount of o il leakage took place.

A yellow pine telephone pole which shows evidence of initial decay along the ground line, as shown in section in Figure 2, is selected` for use with the package 1,0. Dirt D is removed 'for about 18 inches below the ground line GL around the pole 14, and the surface of the pole 14 is cleaned to remove dirt and minor decayed particles. Then the film 13 is cut along lines C, C (indicated by arrows in Figure 1) along the opposite edges of the sheet 11 with a pen-knife or other suitable instrument. Next, the bottom portion 13u of the film 13 is stripped from the sheet 11 (although for convenience in this operation the package is turned upside down and the removed film portion 13o is taken from the top of the package). Next, the fabric sheet 11 is placed in direct contact with the surface of the pole 14 and the resulting package 10 (which now has the film layer 13a removed therefrom) is wrapped around the pole 14, as shown in Figure 2, from substantially 12 inches below the ground line GL to about 6 inches thereabove. The dirt D may then be filled in around the ground line to retain the wrapped package 10 in contact with the pole 14, or a strap or belt of metal sheet or other suitable fastening material may first be wrapped around the bottom of the package 10 to retain the same in position, or the film 13 may be tacked at the edges. After about one month, it will be found that the oil and Pentachlorophenol have penetrated the telephone pole 14 to a depth of about l/s inch along the ground line GL. If a cedar or fir pole is used the penetration is less, in the order of 3A; inch.

It will thus be seen that the instant invention is uniquely advantageous in the simplicity of application of the preservative package. This can be accomplished in a matter of a few seconds simply by Wrapping the package 10 around the pole, whereby application of the preservative rover the entire critical surface of the pole 14 is assured, loss of the preservative through spillage, etc. is avoided and the very substantial inconvenience of contacting the preservative grease with tools, clothes, etc. is completely eliminated.

Similar results can be obtained using heavy grade paper in place of the muslin, or using other polyvalent metal salts of the fatty acids. Other compositions which can be obtained from the following formulations may also be used to produce similar results:

Formulation Il v Parts Pentachlorophenol 15 Aluminum stearate e 8 Root heavy thermal sidecut No. 105 77 Formulation III Pentachlorophenol 13 Aluminum stearate 6 No. 200 diesel oil..-.`. 8l Formulation IV Pentachlorophenol 10 Aluminum stearato 12 Denver No. 3 oil 78 Formulation V It will be understood that modications and variations may be effected without departing from the spirit and scope of the novel concepts of the present invention.

I claim as my invention:

l. A wood preservative package comprising a porous fibrous oil and water permeable sheet, a layer on one side only of said sheet of an inert oil-base carrier of grease-like consistency containing at least 2% of pentachlorophenol, and a synthetic resinous oil and water impervious film completely enclosing the sheet and layer.

2. A method of preserving a wooden object which comprises (l) providing a Wood preservative package comprising a porous fibrous oil and water permeable sheet, a layer on one side only of said. sheet of an inert oil-base carrier of grease-like consistency containing at least 2% of pentachlorophenol, and a synthetic resinous oil and water impervious lm completely enclosing the sheet and layer; (2) removing the film. `from the side of the sheet opposite said layer to expose the sheet; (3) and wrapping the wooden object with the exposed side of the sheet in direct contact with the object.

3. A Wood preservative package comprising a porous fibrous oil and Water permeable sheet of fabric, a layer on one side only of said sheet of an inert oil-base carrier of grease-like consistency containing at least 2% of pentachlorophenol, and a synthetic resinous oil and water impervious film completely enclosing the sheet and layer.

4. A wood preservative package comprising a porous fibrous oil and water permeable sheet, a layer on one i side only of said sheet comprising an aromatic petroleum oil, a polyvalent metal salt of a C12-C18 fatty acid, and at least 2% of pentachlorophenol, and a synthetic resinous oil and water impervious film. completely enclosing the sheet and layer.

5. A wood preservative package comprising a porous fibrous oil and water permeable sheet, a layer on one side only of said sheet of an inert aromatic petroleum gel carrier of grease-like consistency containing at least 2% of pentachlorophenol, and a polyethylene film completely enclosing the sheet and layer.

6. A wood preservative package comprising a muslin sheet, a layer on one side only of said sheet of an inert carrier of grease-like consistency comprising an aromatic petroleum oil, a polyvalent metal salt of a C12-C18 fatty acid, and at least 2% of pentachlorophenol, and a polyethylene film completely enclosing the sheet and layer.

References Cited in the file of this patent UNITED STATES PATENTS 

2. A METHOD OF PRESERVING A WOODEN OBJECT WHICH COMPRISES (1) PROVIDING A WOOD PRESERVATIVE PACKAGE COMPRISING A POROUS FIBROUS OIL AND WATER PERMEABLE SHEET, A LAYER ON ONE SIDE ONLY OF SAID SHEET OF AN INERT OIL-BASE CARRIER OF GREASE-LIKE CONSISTENCY CONTAINING AT LEAST 2% OF PENTACHLOROPHENOL, AND A SYNTHETIC RESINOUS OIL AND WATER IMPERVIOUS FILM COMPLETELY ENCLOSING THE SHEET AND LAYER; (2) REMOVING THE FILM FROM THE SIDE OF THE SHEET OPPOSITE SAID LAYER TO EXPOSE THE SHEET; (3) AND WRAPPING THE WOODEN OBJECT WITH THE EXPOSED SIDE OF THE SHEET IN DIRECT CONTACT WITH THE OBJECT.
 6. A WOOD PRESERVATIVE PACKAGE COMPRISING A MUSLIN SHEET, A LAYER ON ONE SIDE ONLY OF SAID SHEET OF AN INERT CARRIER OF GREASE-LIKE CONSISTENCY COMPRISING AN AROMATIC PETROLEUM OIL, A POLYVALENT METAL SALT OF A C12-C18 FATTY ACID, AND AT LEAST 2% OF PENTACHLOROPHENOL, AND A POLYETHYLENE FILM COMPLETELY ENCLOSING THE SHEET AND LAYER. 